Recorded motor control system



Sept. 28, 1954 c. JOHNSON 2,690,532

RECORDED MOTOR CONTROL SYSTEM Filed May 18. 1949 7 Sheets-Sheet J.

JNVENTOR. CLARENCE JOHNSON ATT OR Y FIG. I

Sept. 28, 1954 c. JOHNSON 0, 3

RECORDED MOTOR CONTROL SYSTEM Filed May 18, 1949 7 Sheets-Sheet 2 EQ'1 BE EE E a 25 ROTATION MOTOR M STOPPED RANGE BEL 91 P AXIS OF WIRE ENVELOPE OF MAGNETISM PATTERN 0F MAGNETISM INVENTOR.

CLARENCE JOHNSON A T OR NEY FIG. 2

p 23, 1954 c. JOHNSON 2,690,532

RECORDED MOTOR CONTROL SYSTEM Filed May 18, 1949 7 Sheets-Sheet 3 E 2 F- LL! 2 a LL. 0 m uJ m o m o EFFECTIVE LENGTH OF WIRE FORWARD C Q E a D Lu 0 UJE EL m E E e: 0 g 24 o 4 u. 50 REVERSE G a:

I m 0) 0: I w a: 2.

, INVENTOR. CLARENCE JOHNSON FIG. 3

Sept. 28, 1954 c. JOHNSON 2,690,532

RECORDED MOTOR CONTROL SYSTEM Filed May 18, 1949 7 Sheets-Sheet 4 FIG. 5

IN V EN TOR.

CLARENCE JOHNSON BY W gifM Sept, 2, 1954 Filed May 18, 1949 TRAVEL OF TOOL C. JQHNSON RECORDED MOTOR CONTROL SYSTEM 7 SheatsF-Sheet 5 :5 AMPLIFIER I60 TEMPERATURE INVENTOR. CLARENCE JOHNSON AT RNEY TRAVEL OF CARRIAGE 7 m M OT W WC m m C D E D R o C E R Sept. 2, 154

'7 Sheets-Sheet 6 Filed May 18, 1949 INVENTOR.

' CLARENCE JOHNSON BY I AT RNEY C. JOHNSON RECORDED MOTOR CONTROL SYSTEM Sept. 28, 1954 7 Sheets-Sheet 7 Filed May 18, 1949 INVENTOR. CLARENCE JOHNSON ww Jomkzoo mOPOE mm u h-7524 Patented Sept. 28, 1954 UNITED STATES PAT FFICE 16 Claims.

My invention relates to method and means for the storing and reproduction of intelligence, and more particularly for the storing and reproduction of programmed control signals.

The invention lies in the art of magnetic wire recording which has provided machines wherein sound is recorded magnetically on a moving filament such as a paramagnetic wire subjected to a magnetic field varied in accordance with a sound wave to be recorded. Thereafter the sound wave may be reproduced by subjecting a pick-up device to the magnetic field emanating from the permanently magnetized wire as the latter is moved at recording speed past the pick-up device. The elongated recording medium may be in the form of wire, metallic tape, magnetic paper tape, or the like, although certain forms provide advantages as compared to others. Various forms of transducer heads, erasing heads, reproducing pick-ups, reel winders, and other apparatus have been invented and are known in this art.

I believe that I am the first one, however, to consider the permanently magnetized elongated member as a cam or program cam useful in machine or similar operations in place of known mechnaical cams or program means, and having many advantages thereover. I have conceived of method and means for so magnetizing an elongated medium that the magnitude, or rate of change in magnitude, of magnetization along the length of the medium varies in accordance with a predetermined pattern or program, to the end that it is in the nature of a cam or pattern which may be reproduced many times with high fidelity.

The invention is readily adapted to the control of machine tools to the end that large quantities of an article may be replicas of a desired shape. Or the invention may be included in the control of processes to program a series of operations or the like. In similar manner it may be useful in sequential operations upon an object or assembly, or in the assembly or packaging of articles. In fact, it is useful in most systems or operations which have in the past found use for cams, cam action, programming, sequential operation, or the line. Broadly the invention pertains to the storing upon a magnetizable elongated member of desired cam or program intelligence useful in the control of operations or the like. So far as I am aware no one has previously used this method and apparatus in the control of motion, actions, operations, or the like.

In the drawings:

Fig. 1 is a diagrammatic showing of my invention embodied in the control of a lathe.

Fig. 2 is a graph of motor operation in connection with Fig. 1.

Fig. 3 is a graph of a different motor control arrangement.

Fig. 4 is an electric circuit diagram for a twoelement control.

Fig. 5 is an electric circuit diagram for a d-c pick-up.

Fig. 6 is a plan view of a portion of a lathe under single-element control.

Fig. 7 is a graph in connection with Fig. 6.

Fig. 8 illustrates my invention applied to a vertical boring mill.

Fig. 9 diagrammatically illustrates a further embodiment of my invention in connection with furnace control.

Fig. 10 diagrammatically illustrates an arrangement embodying my invention in another type of temperature control.

Fig. 11 is a graph in connection with Figs. 9 and 10.

As is well understood by those familiar with the art, in some machine tools, such as lathes, the tool is moved longitudinally and transversely of the work piece, which except for rotation about its center remains stationary. In other machine tools, such as some types of milling machines, the work piece may be moved in two directions, while the tool except for rotation about its axis remains stationary. In some other types of milling machines and in some die sinking machines the tool may be moved in one, two or three directions and the work piece may also be moved in one or more directions. In all instances, it will be observed, however, that it is the relative movement between the tool and work piece that causes the work piece to be formed to a desired shape. As one specific embodiment of my invention I have chosen to illustrate and describe my invention incorporated in a lathe, wherein the work piece, except for rotation about its center, remains stationary and the tool is moved transversely and. longitudinally thereof. As another specific embodiment of my invention I have illustrated my invention applied to a milling machine wherein the tool, except for rotation about its center, remains stationary and the work piece is movedin two directions in order that the tool may cut the work piece to a desired shape. It will thus be evident that my invention is applicable to a wide variety of machine tools, and that when I speak of relative movement between the tool and work piece I include either an arrangement where the tool is stationary and the work piece moves, or the work piece is stationary and the tool is moved, or a combination of the two.

Referring now to Fig. l, I show my invention applied to an engine lathe I having a head stock 2 adapted to be rotated at desired speed by a motor M and having a tail stock 3-. A carriage 4 is movable longitudinally along the bed of the lathe in suitable ways 5 and supports the tail stock 3. Also movable longitudinally along the bed of the lathe, in suitable ways 6, is a carriage l. Mounted on the carriage l is a cross-slide 8, movable on ways transversely of the bed of the lathe.

The cross-slide 8 is provided with an adjustable tool support 9 in which is secured a tool 13. Transverse movements of the tool it are produced by means of an electric motor M driving through the necessary gear reduction 12, a worm or screw l3 for positioning the cross-slide 8 transversely of the bed of the lathe. Longitudinal movements of the tool l0, that is movements of the tool parallel to the bed of the lathe, are produced by means of the lead scre. it, through the agency of motor M and gear reduction l5.

Supported by the head stock 2 and tail stock 3 is a work piece It which for illustrative purposes is shown as being formed to a parabolic shape by the tool H1. The particular shape has no significance, it being apparent as the description proceeds that by my invention a Work piece may be formed automatically to any desired contour. My invention lies primarily in the method of and apparatus for controlling the motors M M and M Prior systems for contour machining have used patterns, cams or templets, shaped to dictate the path of a tracer element controlling the cutting path of the tool along the work piece to form the latter to the desired contour. By my present invention I make use of the storing up of control signals by magnetically influencing magnetizable bodies and specifically by impressing a predetermined pattern of magnetism upon an elongated linear paramagnetic recording medium such as a wire or tape; thereafter utilizing the magnetic pattern to control power means for relatively moving the tool and work piece.

In connection with Fig. 1 I will describe my invention as utilizing a wire as the storing medium, although I may equally as well utilize a metallic tape or what is termed a magnetic paper tape which may be a paper tape coated with a magnetic substance capable of retaining a magnetic trace left by a recording head. In some arrangements, coated paper tape may be preferable over wire or metallic tape as it may be moved closer to the recording or reproducing transducers. Furthermore, there is no self-transducer efiect and usually no level-wind mechanism in reeling is required.

The motors M M and M are simultaneously, but separately, controlled by a wind-and-rewind system I? having three elongated paramagnetic storing media in the form of wires l8, l9 and 20. The wire is preferably a steel wire of about .004" diameter and will of course be of considerable length.

In connection with wire [8 I show a pair of spaced reels 2!, 22 interchangeably receiving the linear magnetic storing media I8. Similarly, reels 23, 24 and 25, 26 wind and rewind the wires l9 and 20. Reels 2i, 23, 25 are carried by a shaft 2'. having a driving gear 28. The reels 22, 24, 26 are carried by a shaft 29 having a driving gear 30.

For rotating the gears 28 and 30, and thus the shafts 27 and 29, I provide a motor M having the necessary control 3i for starting or stopping the motor. The motor rotates in a single direction and may be provided with hand adjustable speed control for basically setting the speed at which it operates. The motor drives a shaft 32 and may have fixed or adjustable gear reduction to the end that shaft 32 rotates always in one direction at preselected speed, or is stopped.

Slideably mounted on the shaft 32 is a gear 33 shown in driving relation to the gear 28 so that when the motor M is energized the shaft 21 is rotated and wires [8, l9 and 20 move from right to left (on the drawing) thus unwinding from reels 22, 24, 23 and winding on reels 2!, 23, 25 respectively.

The shaft 32 is provided with a solenoid 34 (diagrammatically shown) so arranged that when energized it slides the gear 33 along a spline on the shaft 32 out of driving engagement with gear 28 and into engagement with a reversing gear 35 for driving the gear 36. Thus when the solenoid 3 is deenergized, the reels 2|, 23, 25 are winding and the reels 22, 2-3, 26 are unwinding; but when the solenoid 34 is energized then the reels 22, 24, 26 are winding and the reels 2|, 23, 25 are unwinding.

The control box 3i may also contain the necessary mechanism by which solenoid 34 is selectively energized or deenergized; and the selectivity may be accomplished according to a program belt, tape, or wire 38 driven at a constant speed by a motor M I have very diagrammatically shown the belt 36 as having a number of protuberances thereon for actuating the control 3i but the belt 36 may have holes, slots, or other arrangements for accomplishing the sequential or program actuation of the solenoid 34 as well as the stopping or starting of motor 1V]: to the end that the direction and time of operation as well as the stopping and starting of reels 2!, 23, 25, 22, 24, 23 may be desirably accomplished in preselected manner.

Adjacent the wires I8, [9, 2D I locate the pickup devices 40, GI, 42 respectively; shown diagrammatically as windings subject to the magnetic field emanating from the wires as the latter are moved at predetermined speed past the pick-up devices. Preferably the winding is on a core presenting a pair of pole pieces past which the record wire is moved; the flux emanating from the magnetized record wire being used to pass a varying flux through the pole pieces and thereby induce a potential in the winding,

The potential or current induced in winding 40, 4| or 42 is used in the control of motors M M and M respectively and may, in my invention, be used in somewhat different manner in the control of the difierence motors.

The magnetic shaping of the elongated mediiun (wire 18, i9 or 23) is not necessarily the same for the three wires but is so proportioned and coordinated that the three programs or magnetic cams cooperate to produce a resulting operation of motors M M and M whereby the relative movement of the tool I3 and work piece I6 produces the desired configuration of the work piece. No one of the three wires individually has a magnetic shape or pattern corresponding directly or proportionately to the desired contour of the work piece, but the magnetic patterns of the three wires, controlling the three motors simultaneously, results in a cooperative effort producing the final desired work piece contour. I will later explain, however, how I may-combine the control of any two or all threeof the motors from a single wire or tape.

I Considering first the motor M and its control it will be noted that it is adapted to rotate the work piece IS in a single direction and usually at a-uniform speed, although I providethat the speed of rotation may be changed in accordance with a predetermined program determined by the desired shape of the work piece. The potential induced in the pick-up winding v42, through movement of wire 20, is effective in control of motor M through the agency of amplifier 4.3 and motor control 44.

In this description I will refer to the pattern or cam of magnetism stored by the elongated paramagnetic medium as an envelope having a contour determined by the magnitude of magnetization of successive increments of the medium moved past a point of the pick-up. Thus the potential induced in the winding 42, as the wire 28 is moved along, will vary in magnitude in accordancewith the shape of the magnetic envelope of the wire 20. If the bounds of the envelope are parallel to the wire axis the speed of motor M will be uniform and of a magnitude determined by the spread of the envelope. The adjustment of networks 32, 44 may be such as to have a predetermined finite value of envelope with the motor not rotating, in which event a decrease in envelope width will result in reversal of motor rotation.

This operation may be schematically depicted as in Fig. 2 which indicates the axis of the wire as the line of zero magnetism. In this representation the envelope is considered as surrounding the wire with its bounds equal distance from the wire axis. With rotation desired only in forward direction, then the adjustment of network 43, 44

may be such that the motor is stopped when the envelope is zero; any finite value of envelope resulting in a corresponding forward speed. On the other hand, Fig. 2 depicts the motor M stopped with envelope value of five units. A constant forward speed A is depicted at envelope value eight and a similar reverse speed A at envelope value two. Any desired pattern of speed such as a gradual increase B may be attained by the proper shaping of the magnetic envelope.

The motor M is arranged to rotate the lead screw I4, through gear reduction I5, for traveling the carriage I longitudinally along the bed of the lathe. Pick-up 4| is sensitive to the magnetic pattern of wire I9 and, through control network 45, 46, controls the starting of motor M and its operating speed, and thus the travel of the tool ID parallel to the axis of the work piece I6. The operation may be similar to that depicted in Fig. 2

in connection with motor M Motor M and its gear reduction I2 are mounted on an extension of carriage I and thus travel longitudinally of the lathe with tool l0. Transverse movements of the tool, i. e. movements of the tool toward or away from the work piece I B are accomplished by the screw I3, driven by the motor M and gear reduction I2, which moves the crossslide 8 along suitable ways 47. A balancing slidewire 48 is driven by the gear reduction I2 to the end that its value is in step with the transverse position of tool II].

The envelope pattern of wire I8 more closely approaches the desired shape of the work piece I 6 than the pattern of wires I9 and 29. The pickup wire 40 is connected to a bridge network and motor control 49 which joins the motor M and 6.. balancing slide-wireresistance'48. As the envelope of wire I8 changes, the network-49 is unbalanced, resulting in a starting of motor M in proper direction to move the tool toward or away from the axis of work piece I6, and at the-same time move the slidewire 48 to follow up or tend to maintain the network in balance. The motor M is not normally continuously running, as are motors M and M but stops, starts and reverses, at variable speeds, under the dictates of the wire I8 pattern.

In general the three motors M M and M coact under the control of pick-ups 40, 4! and 42 to give a coordinated control of relative movements of the tool and work piece whereby the work piece is shaped to desired form. I have not felt it necessary to explain how the magnetic envelope of the wires I8, I9 and 20 are calculated and impressed upon the wires inasmuch as known methods and transducing apparatus may be employed. It is only necessary to point out that the envelope pattern of the three wires are so arranged that when the wires are driven in synchronism the resultant movements of the three motors controlled thereby will cause a relative positioning of the tool and work piece to the end that the work piece is formed to desired shape.

By way of a practical example, in connection with Fig. 1, I may indicate that the motor M rotates the work piece in proper direction at uniform speed and that the motor M rotates the lead screw [4 in proper direction to travel the carriage I from right to left (in the drawing) at desired speed. If the motor M is stopped then the forward travel of the tool III will turn the work piece I6 to cylindrical form. The diameter of the cylinder will of course depend upon the transverse location of the cutting tool I0 at the time motor M is stopped. If a greater or smaller diameter of cylinder I6 is desired, then the motor M will be energized in proper direction to move the tool III toward or away from the axis of the work piece to the desired diameter of the finished product.

Referring to Fig. 2 it will be understood that an energization of motor M occurs only upon a change in size of the envelope of wire I8 thus so long as the envelope remains of constant size the path of the tool It] will be parallel to the axis of the work piece I6. Upon any change in the diameter of the magnetic envelope of wire I8 the network 49 becomes unbalanced thus actuating motor M to move the tool I0 toward or away from the axis of the work piece I6 and at the same time move the slide-wire 48 to follow up and tend to balance the network. As soon as the envelope is no longer changing the network balances and rotation of motor M ceases. Thus it will be seen that if the contour of the envelope is a gradual taper then the resultant cutting of the work piece I6 will be tapered and to a degree determined by the rate of change in the envelope pattern. This of course is premised upon a uniform speed of motor M so that the tool I0 travels at a constant speed from right to left.

Should it be desired to machine the work piece I6 with a sharp shoulder normal to the axis of the work piece, then when that point on the envelope pattern is reached motor M is stopped thus stopping longitudinal travel of tool Ii], and at the same time motor M is energized in proper direction to move the tool 10 toward or away from the axis of the work piece IE to produce the desired shoulder. It will thus be seen that any normal machined contour may be produced on the work piece by a proper combining of the three envelope patterns.

Normally the longitudinal travel of the tool I is from right to left facing the drawing of Fig. 1 and at what may be termed a normal speed. If the transverse motor M rotates in either direction, thus positioning the tool |fl either toward or away from the axis of the work piece l6, then the speed of rotation of the motor M and consequently the speed of longitudinal travel of the tool I0 is decreased. This proceeds to a limit wherein if the transverse movement of the tool I0 is directly toward or way from the axis of the work piece I5 (as dictated by the envelope patterns) then under this condition the motor M would not rotate and the tool would not travel longitudinally relative to the work piece until the direct transverse motion of the tool had been accomplished. In this way direct 90 degree shoulders are produced on the work piece l6.

For certain operations it may be desirable to provide a 3-element control of the lathe, namely to include with the control of transverse and longitudinal movement of the tool In a control of speed of rotation of the work piece relative to the tool. This is so that the cutting speed of the tool may be held constant, i. e. the speed of rotation of the work when cutting at one diameter to be proportionally greater or lesser than the speed of rotation when cutting at a different diameter. To accomplish such control I provide for rotating the work piece 16 through the necessary gears by the motor M and controlled as previously. In other words the motor would rotate normally in a single direction but its speed of rotation would depend upon the transverse position of the tool I0 and consequently upon the diameter of the work piece at which the tool were cutting.

As I have previously mentioned the control 3|, in conjunction with the programmed belt 36, may be arranged for complete sequential or program operation of the lathe to the end that after the work piece H5 is properly in place one or a series of cutting operations may be performed thereupon by the tool cam with automatic return of the tool to its starting position at the end of each cutting pass. For example the arrangement may be such that the wires l8, l9 and 20 are moved to provide the proper guidance for the tool l8 in a cutting travel from right to left within predetermined limits of travel. Upon reaching a predetermined limit of travel to the left of the drawing the program arrangement may retract the tool l0 away from the surface of the work piece |6, stop (or continue) rotation of the work piece It, back travel the tool ID to its starting position at the right at high speed, and move it forward into cutting engagement with the work for a second cutting pass over the work; all under the dictates of the magnetic patterns on wires I8, I 9 and 20 as well as the programmed belt 35 and control 3|.

In connection with Fig. 2 I have explained one possible operation for such an operating motor as motor M Reference new to Fig. 3 will show a possible motor control, in connection with stored magnetic pattern, where changes in the motor operation are accomplished in accordance with change or rate of change in magnitude of the envelope rather than directly in accordance with the envelope magnitude.

The graph of Fig. 3 might Well represent control of motor M for longitudinal travel of the tool I0. I have plotted this figure greatly out of scale as particularly in connection with the effective length of the wire versus degree of magnetism of the wire. With this arrangement, based on rate of change of the dimension of the magnetic envelope it will be seen that uniform forward speed C will be obtained for a predetermined gradual and uniform increase in degree of magnetism along the wire. The upper curve shows the uniform slope of this relationship whereas the lower curve C shows a uniform forward speed corresponding to the particular slope of the magnetism of the wire. At a different lesser slope D, in the upper curve, a lower uniform speed D of motor M will be obtained, while if the envelope has a space of uniform dimension as designated E where there is no increase or decrease in the bounds of the envelope then motor M is stopped as is the longitudinal travel of carriage I. Referring to the upper portion of the figure if, after a portion E, the envelope increases at a somewhat faster rate than over the portion D this will dictate a new forward uniform speed F in the lower graph. Furthermore, a decreasing taper G will result in a uniform reverse speed of a value depending upon the slope of the magnetic envelope taper.

It will be evident that the arrangement so far described is for substantially uniform longitudinal movement of the tool It) with contouring movement transversely. If it is desired to do the reverse operation such as facing a large disc-like work piece in contoured pattern, i. e. where the transverse positioning of the tool I0 is substantially at a uniform speed and the longitudinal positioning of the tool I!) is in accordance with a contouring pattern then this may readily be accomplished through the necessary switching mechanism whereby the slidewire 48 is made ineffective for the motor M and a slidewire 5B is brought into play for the motor M In Fig. 4 I show a wiring diagram of what I term a Z-element control wherein the motors M and M are under the control of a single pick-up device 5| which is located adjacent a moving wire having an envelope pattern so proportioned as to produce the desired configuration of the work piece It by the two motors M and M simultaneously controlled from the one envelope pattern.

The motor M for positioning the screw |3, has stator windings 52, 5'3 constituting running coils electrically degrees apart. The motor is provided with a capacitor or condenser 54 which, when the motor is rotating, is in series with either the winding 52 or the winding 53 depending upon desired direction of rotation. Such a motor runs as a Z-Dhase A.C. motor and not only may be reversed as to direction of rotation but is susceptible of speed control when rotating in either direction. When the output of the transformers 55, 56 is equal the rotor does not rotate, but with an unbalance in output of the transformers 55, 5B the rotor rotates in predetermined direction and at a speed depending upon the extent of the unbalance of output of the transformers. The output of tubes 51, 58 is controlled by a circuit including the grids respectively of said tubes as well as including the pick-up device 5|. If there is no induced potential through the pickup device 5|, 1. e. no value of magnetic envelope of the pattern the tube 58 passes current and the tube 57 does not. When a maximum potential occurs at the device 5|, then the tube 51 passes current, but the tube 58 does not. At all intermediate values of potential at the device 5| the two tubest'LtB-pass proportionate amounts of current and proportionally or differentially vary the impedance of the secondaries of transformers 55, 56, resulting in a corresponding variation in energization of the field windings E2, 53, and ii the energization of the windings is unbalanced, then rotation of the rotor is in predetermined direction and at a predetermined speed, dependent upon the amount of unbalance.

For positioning the cross slide 8, as well as the tool [0, in a longitudinal direction parallel to the axis of the work piece it I provide the electric motor M illustrated in Fig. 4 as a capacitor-run alternating current motor having two windings 59, an electrically 90 degrees apart and a capacitor 6|. When current flow is directly through one of the windings 59 or 60 and simultaneously through the other winding in series with the capacitor Bl the motor rotates in desired direction.

The arrangement is such that normally the motor M rotates in but a single direction but at a variable or controllable speed. Normally, the longitudinal travel of the tool I!) is from right to left facing the drawing of Fig. 1' and at what may be termed a normal speed. If the transverse motor M rotates in either direction, thus .positioning the tool I!) either toward or away from the axis of the work piece l6, then the speed of rotation of the motor M and consequently the speed of longitudinal travel of the tool Ill, is decreased. This proceeds to a limit wherein if the transverse movement of the tool IE3 is directly toward or away from the axis of the work piece it (as dictated by the pattern envelope to which the pick-up device Si is sensitive) then under this condition the motor lVI would not rotate and the tool would not travel longitudinally relative to the work piece until the direct transverse motion of the tool had been accomplished. In this way direct 90 degree shoulders are roduced on the .work piece I 6.

I show in Fig. 4 an electric circuit for control of the motor'M such that it normally rotates in but a single direction and what may be termed a normal speed when the motor M is not rotating; in other words, when the output of the transformers 55, 55 is balanced. If the motor M begins to rotate in one or the other of its two directions then the speed of rotation of the motor M is decreased. When the motor M is rotating at its maximum speed in either direction then the motor M is stopped.

A conductor fi joins the common terminal of resistances '83, 611 with the common terminal'of the transformer secondaries 55, 56 but interposed between the said secondaries are direct current saturating windings t5, whose common terminal is joined to the conductor 62. These saturating windings 65,-55 are bridged by condensers and are so arranged as to be oppositely effective in saturating the core of a saturable core reactor having an 'A.C. output winding 81.

I illustrate a double pole double throw switch 68 which under normal operating conditions is in the position illustrated. One pole of said switch joins the alternating current output winding 68 of a saturable core reactor iii with the terminal 7! of the motor M If the envelope of the pattern dictates a cylindrical turning of the work piece l6 then the potential value of the pick-up device is normal, the tubes 5158 pass equal amounts of current,

' the impedance of the transformers'i'm, 55 is equal,

and the motor M is stationary. Under such conh -dition it is desired that the motor M be operating in. its normal direction at its normal speed. saturating effects of the windings 65,66 is equal and in opposite direction, thus permitting a minimum flow of alternating current through the output winding El and the motor M in opposition to the constant bias effect of the reactor Ill.

While in Fig. l I show the slide-wire #8 as a tie-back means to stop motion of the motor M when transverse movement of the tool H] has satisfied the demand of the envelope pattern and to result in cylindrical turning for any instant or period of time, in Fig. 4 I show a tie-back .means comprising an adjustable resistance 12 whose movable part is positioned by the motor M in comprising a balancing efiect to overcome or ofi'set the potential induced in the pick-up device 5 l. Thus, movement of the motor M results only when there is an unbalance between El and i2 and any motion of motor M serves to readjust element '12 to bring about a rebalancing and stopping of the motor M Upon change in the potential of pick-up 5| in either direction from a previous position value the current flow through the transformer secondaries 55, 56 is unbalanced thus unbalancing the D.C. saturating effect of the windings 65, 55. It is immaterial as to whether or 66 predominates, as regardless of the direction of predominance it is the difference between the two which provides an increase in saturating effect upon the reactor and an increase in passage of alternating current through the output winding El in opposition to the constant value of alternating current passing through the output Winding 69 of the bias reactor '59. As the transformers 55,55 continue to .a maximum of unbalance, corresponding to maximum speed of the motor M in one direction 'or the other, the alternating current flow through the winding 61 opposes that through the winding 69 until they reach a value of equality whereupon the motor M ceases'to rotate. In order that there may be no possibility of the motor M reversing its direction of rotation the value of the bias current through 69 is slightly greater than that ever attained through the winding'fil.

'Theoretically the motor M will not cease rotating, but practically its speed of rotation diminishes to a point Where friction and load actually stop rotation.

It will thus be clear that the motor M normally rotates in but a single direction and at a speed from normal varied downward to zero, dependent upon the increase in speed of rotation of the motor M and independent of the direction of rotation of the motor M In order that a rapid return of the tool II} from left to right may be accomplished at maximum rotating speed of the longitudinal travel lead screw i i in proper direction the switch 68 when thrown in position opposite to that shown in Fig. 4 properly connects the windings 59, 66 directly across the power source so that the direction of rotation of the motor M is reversed.

In Fig. 5 I show an electric network such as may be used in the control of motor M if the pickup device it has induced therein a low value D.-C'. potential. The reactor-converter circuit 8!] may be of the type disclosed in Patent 2,447,338 to Hornfeck. The output of the bridge 86 suplies the amplifier and motor control circuit 8i for the motor M while the slidewire it provides the necessary tie-back to the bridge 80. The result is that a low level D.-C. input is converted into a greatly amplified A.-C. output useful in operating the reversingmotor M Throughout this disclosure I indicate the work piece is formed to correspond to the shape of the magnetic pattern or envelope. By such language I do not intend to imply that the work piece is brought to the exact shape of the pattern but as will be evident to those familiar with the art the pattern will be formed so that the ultimate shape of the work piece produced is that desired and that therefore the shape of the work piece may differ from that of the pattern by the amount of angularity, etc. in the mechanism. While the pattern or patterns must correspond to the desired workpiece, they are not necessarily identical in contour and therefore the term correspond implies that the magnetic pattern or envelope is purposely designed to result in a desired contour of the work piece to be produced. In speaking of profile or contour I mean the forming of a work piece to a shape as dictated by that of the pattern and without any specific or limiting meaning being given to the terms profile and contour.

Referring now to Fig. 6 I show therein an adaptation of my invention to a single element contouring ar angement for a lathe arranged, in certain instances, to perform the operation previously described as accomplished by the two separate motors M and M The lathe parts as shown in Fig. 6 bear the same numerals as those of Fig. 1, where identical. Mounted on and carried by the cross-slide 3 is an angularly positionable compound rest 5 forming a support for the tool l0. Movements of the tool it longitudinally relative to the work piece 16 are produced through the agency of the normal lead screw Hi and through the agency of the motor M which is arranged to position the compound rest 9 through the agency of the screw :3. The motor M gear reduction l2, slidewire 8, and screw [3 are supported by and carried by the compound 9, angularly positionable therewith, positionable by and with the cross-slide 8 transversely of the axis of the lathe, and carried by the carriage l longitudinally of the lathe when the carriage I is so positioned through the agency of the lead screw M or otherwise.

A study of Fig. 6 will show that the top slide of the compound 9 (which carries the tool is positionable relative to that portion of the compound 9 fixed to the cross-slide 8, through the agency of the screw [3. If the angularly positionable upper portion of the compound 9 is so turned that the axis of the screw I3 is normal to the axis of the lathe and work piece, then transverse movement of the cross-slide 8 will result in transverse positioning of the tool :9 normal to the axis of the work piece. If, however, the angularly positionabl upper portion of the compound 9 is so moved that its center line (as in Fig. 6) is at an angle of 45 degrees with the axis of the work piece, then (with no longitudinal movement of the carriage 1) the tool may be moved toward or away from the work piece l through the agency of the screw is at an angle of 45 degrees to the axis of the work piece.

It is apparent that other angular relationships may under certain conditions be more advantageous. The exact angular relationship depends upon various things, such as the desired shape and finish of the work piece, the speed of the lead screw l4, and the speed of travel of the screw 13. The speed of the screw is is preferably several times faster than the speed of travel of the carriage l by the lead screw [4. If the travel of screw I3 is fast enough relative to the carriage, then the cutting of the work is dependent only on the pattern.

In the example illustrated in Fig. 6 I preferably travel the carriage I from right to left at a uniform speed through the agency of the regular lead screw Hi. The tool is moved toward or away from the axis of the work piece by the motor driven screw [3. The resultant positioning of the tool it relative to the work piece is a vector resultant of the two motions. By proper choice of the speed of such movements the work piece I6 y be turned to a taper or to have straight shoulders normal to the axis of the work piece. I will now describe the conditions under which three general types of cuts may be taken, and it will be appreciated that intermediate types of turning may be accomplished by modifications of adjustments to be mentioned.

A. Cylindrical turning.--Assume uniform preselected speed of rotation of the work piece l5 and uniform preselected speed of travel of the carriage 1 alon the ways 6 from right to left. The tool to is moved toward the axis of the work piece until it cuts to the required diameter. Thereafter the screw is is not moved and cylindrical turning of the work piece is accomplished.

B. Taper turning.-Assume again the uniform preselected speed of rotation of the work piece 16 and the uniform preselected speed of travel of the carriage I along the ways 6 from right to left. Assume that the desired taper of the work piece is to start with a minimum diameter at the right and gradually taper to a maximum diameter at the left. The screw 13 is used to advance the tool in until it cuts the desired minimum diameter of the taper. Thereafter, as the tool is carried by the carriage I from right to left, the screw [3 is uniformly retracted, resulting in the work piece being formed to a taper whose slope is determined by the envelope pattern, the speed of longitudinal travel of the carriage I, and the speed of retraction of the tool by means of the screw I3.

C. Shoulder turning.-Utilizing a standard or commercial lathe I again assume a uniform preselected speed of rotation of the work piece 16 and the uniform preselected speed of travel in the carriage 7 along the ways 6 from right to left. If the turning of the work piece at a given diameter point requires an immediate change in diameter, the desired result is a straight shoulder or step on the work piece with the face of the shoulder lying in a plane normal to the axis of the work piece. If the screw I3 is retracted uniformly at the correct speed the result or vector cutting travel of the tool It follows a path which is the resultant of two interrelated movements, namely, uniform movement from right to left axially relative to the work through the agency of the lead screw 44, and a retraction along a line 45 degrees from the axis of the work through the agency of the screw l3. Proper choice in speed of retraction of the screw l3 (relative to the speed of travel of the carriage 1) produces a movement of the tool it) in a direction normal to the axis of the work piece and a sharp step or shoulder is out upon the work piece. A modification in relation between the speed of movement of the carriage and the speed or retraction by the screw [3 results in taper turning as previ- "ously mentioned. course, obtained in the rotational amount and apeoasa Such a modification is, of

direction of screw t3 by thecooperation of the pick-u "M with the-magnetized" wire 18.

I have'foun'd thata relationship of 45 degrees is the most universally applicable relative position ofthe parts. "Thispof course,-is'because 45 degrees is' mid-way of'the' 90 degreeangularrrelation desired-between the axis of the work piece and'the face "of a shoulder. Refer now to Fig. '7. The possible-speed of'tool travel by means of screw I'3 from iA'tO'B is several times the lead screw speed'of pthe-carriage 1 from B 'to'jC although the actual speed ofretraction-by "screw l3 from A-toTB is dictatedyby the'en- "'velope'pattern. 'If the angle ABC is 45 degrees then the resultant travel-of the'tool'will be AC and inasmuch as AC'='CB the cutting speed of the tool in machining the-shoulder will be'the "samepand the'finish will'be the same, as if the tool were cutting 'cylindrically' along a path BC.

If 'the'angle is changed to 60idegrees;forexample'as DBC, then'thafinish along DC will benearly-twice as coarse as. it wouldhave'been along a pathBC. 'This'issometimes'desired in step-shafts. If the angleis 'reduced'to BO-degrees-as EBC then the "finish'ontheshoulder will be finer than itwouldhavebeen along the path BC.

The mathematical analysisof theunit is based upon the-sine law.

a c sin-.p sin-n sin 1), sin nand c are'iknown c (sin-p) "The finish is inversely proportional to the feed per revolution, therefore if thefeedalong c is of and theresultant-feed-along' a -is'a) at 45 11 and n are the same. and

.500 (If Cf Cf It will now "be apparentwthatzI-have been able, through the agency-'of :my ;present, inven 'tion, to accomplish shoulder putting-as forzex- "ample in step shaft-turning,-with a single-motion attachment. In the :preceding description, 3

with-the carriage I traveled from? right'ato-left, I am able to produceshoulders-ior'steps :going from asmaller to a larger diameter. It isnot practical with the same-setup and:operation: to

produce steps going from-a larger to a smaller diameter. To produce'such shouldersitwould be necessary to angularly move the compound 9 clockwise approximately "90 :degrees and then 'travel-the-carriage.from left'to; right. A practical solution is, if :the .step shaft is to have shoulders of both types, toffirst'cutall"ofxithe shoulders in one direction-and then to reverse the work and produce the remaining shoulders.

This obviously would .be accomplished in batches, i. e. a small run::of:=shafts:might be external turning of work .pieces. contour horingis desired it is only necessary to replace the tool- Ill by the proper'boringbar and operate upon" the far side of the cavity in exactlythe same manneras described for external 7 lead *screw It alone. described the gear ratio for the lead screw 14 WOUTd always be pitched slightly greater than "put through thermachine to produce the turning in steps in: one direction and" then' the complete "batch to be run through after necessary =practical -in production to grind a tool with a proper rakeand relief for cutting around degrees of the tool.

The particular work piece I 6 illustrated in Fig. 6 is a double disc valve part. This is an ideal production piece' for the apparatus being described'inasmuch'as the surfaces X are to be machined to a predetermined shape Whereas the "surfaces Y may be left unmachined. The work piece |6 is usually-a casting or forging andthe original relatively rough unmachined surfaces Y are notthe working surfaces, and therefore do-not need to'be machined. Obviously the desired contour of the surfaces X is incorporated in the envelope pattern of the wire I8.

' 'Thedescription so far has been concerned with If internal turning. Face plate turning may be accomplished in exactly the same manner and with the same limitations asdescrihed in connection with external turning. In connection with Fig.

:8 I 'Wi'llltltfll describe an improved method of overcoming some ofthe limitations previously mentioned in connection with the lathe and these as described'for a vertical boring mill are equally-applicable in faceplate turning as 'will bereadily apparent.

A further specificuse'for my inventionis in :onnection withthe winding of'springs where thenpitch 'and lead may vary from one batch to another-and-with difierentsizes of material and .iof spring-or'thexpitchand lead may vary desirablyin a singletspring. '1 preferably provide a rotating core or mandrel on which the spring =is'to'be :woun'd. A tool it is replaced'by-a wire guide through which the wire is passed. or pulled 'iby the winding operation on the mandrel. essential thatthe guides move along the mandrel at a speed-determined by the desired pitch It is of' the spring.

Referring to :Fig. '6 preferably the compoundS wouldxbe placed at approximately GOdegrees to the axis of the mandrel sothat the retraction of :the holder, through the agency of screw (3, would hear the' proper relation to the lead screw travel of the carriage l. The envelope pattern of the wire' is. mayxhave gradual inclination or slope relative tothe axis of the work piece in a direction such that acontinual uniform retraction of the tool through the agency of the screw 53 woulcl'be accomplished. Proper shaping of the envelope patternwould result in a vector move 'ment of the wire guide axially of the mandrel at a speed slightly less than that produced'by the Withthe arrangement as the desired pitch of the spring and thus a uniform retraction of the tool by the screw 13 would slow down the carriage travel rates to the desired rate.

Referring now to Fig. 8 I show therein a heavy duty vertical boring mill as used in making tire molds, for example, or other large molds contain ing concentric depressions or cavities. The mill is of a common type and I have therefore felt it unnecessary to show many of the details, such for example as power means for moving the saddle or head or for rotating the work table. In general, the work table 85 is rotated in desired direction at a preselected uniform speed carrying thereupon the work piece 86 which is to be formed by a single point cutting tool 8! to the desired shape through the dictates of the envelope pattern of the wire 18 as scanned by the pick-up winding 40.

A saddle 88 is vertically positionable along columns 88. A head 90 is horizontally positionable along crossrails 9| on the saddle 88. The head 33 corresponds in general to the crossslide 8 of the lathe, Fig. 1. Mounted on the head as and angularly positionable in a vertical plane is a swivel 92 having a tool carrying ram 83 positioned by the screw l3 from the motor M I have indicated that the ram 93 is positioned on the head 98 at about 45 degrees to the horizontal and with the tool 81 engaging the left-hand wall of a generally semi-circular cavity.

The table 85 and work piece 86 are rotated past the single point cutting tool 81. The head 98 is moved at a preselected uniform rate of speed from left to right in the drawing, and during such movement the tool 81 is positioned by the ram 83, through the agency of the screw [3, toward or away from the work table 85 along the angle of inclination of the ram 93 and under the dictates of the envelope pattern of wire i8.

Preferably the envelope pattern is so shaped as to produce the desired contour 95 on the work piece down to the greatest depth of the cavity of the mold. As the head 90 moves to the right the pattern controls operation of motor M so that the surface 95 is machined to the lowermost point, and thereafter a portion of the pattern is so shaped as to idle the tool 81 along a space incline from the bottom of surface 96, toward the right, to effectively clear the portion 96 of the work piece. Continued travel of the head 90 to the right performs a cutting operation (under the dictates of the pattern) across the surface 91 until the tool reaches a point near the axis of rotation of the table 85 and work piece 85. The operator (or a control 3|) then reverses the direction of rotation of the table 85 and work piece 86 while the tool 81 passes over the already machined surface 98 and starts to cut the contour 99 (which is the contour desired 96) under the dictates of the envelope pattern. Continued motion of the head 90 to the right follows the envelope pattern over a space incline to avoid the tool 81 engaging the machined surface Hill (which is the surface 95).

Thus it will be seen that a machining cut is taken across the entire surface of the work piece 85 by one continuous movement of the head He from left to right, it being necessary only to reverse direction of rotation of the table 85 and work piece 88 as the tool 8? passes the axis of rotation. During the initial half of its left to right travel the tool 8'! machines the surfaces 95, 9'1, 98, 99 and during the latter half of its left to right movement it machines the surfaces I00, 96. In this manner the only change or adjustment necessary is a reversal of rotation of the table and work piece 36 and this operation is readily accomplished through the program of recording medium 18 and/or the elements 3| and 36 (as seen in Fig. 1). It is not necessary to make any change in the angular position of the compound 92 relative to the carriage 90. Successive roughing and finishing cuts may be taken through prearrangements of the envelope pattern and/or the elements 3|, 36.

It is apparent that exactly the same method of operation may be utilized in connection with face plate turning with the lathe of Fig. 1 which should pass the tool completely across the face of the work and change the rotation of the work as the center of rotation is passed. The movement of the head along the rails 9| is continuously uniform at a preselected power feed. The movement of the cross-slide 8 across the carriage I (for face plate turning) may be continuously uniform at a preselected power feed.

One particular feature of my invention is in connection with what may be termed as closed cycle operation including a relatively completely automatic cycle of machining operation particularly in a lathe. The normal cutting traverse of the work, by the tool, is followed by a relatively high speed return of the tool to starting position. Such a cycle is completed automatically and the tool stops its travel when it has returned to its initial position and is ready for a second out (if necessary) over the work, or for a time dwell while the operator removes the finished work piece and replaces it with an unmachined work piece. Additionally the program control may be arranged to make the machine completely automatic whereby the unmachined parts are hopper fed, supported in the centers, machined, and released to a receiving container all completely automatically. The combination of the envelope pattern with the elements 3|, 36 will perform such an operation as will be readily apparent to those familiar with the art.

It is equally apparent that such a closed cyle operation may be performed as a combination of mechanical or other limit stops and magnetized wire pattern control. For example the envelope pattern of a moving wire or similar medium may dictate the cutting travel of a lathe tool over a work piece. In combination with this there may be a limit stop provided which, when it is reached by the tool carrier, is actuated to end the travel of the tool in its cutting direction, to bring into play the correct wire pattern dictate for retracting the tool somewhat from the work piece and initiating a rapid return of the tool to its starting position where another travel limit may be engaged. Any or all parts of such a closed cycle operation may be embodied on one or more of the wire patterns or may be embodied in the combination of mechanical stops and wire patterns. Furthermore the sequence of loading and unloading the rough and finished work pieces through the lathe centers may be embodied in envelope patterns or a combination of the same with mechanical movements or limit stops.

In Fig. 9 I show diagrammatically an adaptation of my invention to the measurement and control of temperature in an electric furnace. The general circuit arrangement is disclosed in the copending application of Paul S. Dickey et al. S. N. 71,424 filed January 18, 1949, now Patent No. 2,598,236, granted April 27, 1952, to which reference may be made.

, Referring now to Fig. 9, I indicate at III) a phasev sensitive A. -C. bridge having. fixed resistor arms III, H2 and H3. The fourth arm of the bridge III) is a resistance element H4 located in an electric furnace II5 and sensitive to the tem perature thereof. For balancing the network I provide an adjustable resistance I16 having a movable contact arm III for proportioning the resistance II6 between the arms H2 and I I3.

For positioning the contact arm II! I provide a motor II8 which also positions an indicator I I9 relative to a scale I20 and a revoluble chart I2I, thereby providing an instantaneous indication as Well as a continuous record of the value of temperature to which the resistance arm I I I is sensitive.

The furnace H5 is preferably heated by electric resistance element I22 receiving current from an A.-C; source I 23, which also provides A.-C. supply to the bridge IIII through a transformer I24.

Preferably the bridge arm I I4 is a platinum resistance measuring element. The conjugate corners of the bridge III! are connected to an amplifier I25 and motor control I26 for the motor I I8. For an understanding of the phase sensi tive A.-C. bridge for measuring the resistance of the leg II l subjected to temperature of the furnace I I 5 reference may be had to the Ryder Patents 2,275,317 and 2,333,393. The conjugate voltage supplied to the amplifier I25 assumes a. balance or unbalance and a phase relation relative to the supply voltage dependent upon the magnitude and sense of the unbalance condition of the bridge I I 0. The amplifier I25 selectively controls a pair of motor tubes I21 and I28; The tubes I21, I28 control the amount and direction of unbalance of saturable core reactors I29, I35 for directional and speed control of the capacitorrun motor II8 adapted to position the arms III and H9.

The motor I I8 is of an A.-C. type having windings I'3I and I32 ninety electrical degrees apart and also having a capacitor I33. When alternating current fiOWs directly through one of the windings and simultaneously through the other winding in series with the capacitor, the motor rotates in predetermined direction and at a speed determined by the extent of unbalance of the saturable core reactors I29, I36. It is not necessary to go into greater detail as to the construction and operation of the amplifier I25 and motor control circuit I26, as reference may be had to the above mentioned Ryder patents.

So far I have described a known circuit arrangement. for continuously measuring the temperature of the furnace I I5 and providing a visual indication thereof upon the index I20 and a continuous record upon the chart I2I.

In my present invention additionally I provide a deviation network hit for continuously comparing. the actual value of the temperature or other variable with a desired or standard value or, as in the present case, with a programmed value which is picked off from the wire I8 by the winding M. The network Hid continuously determines the deviation, if any, between the actual and the desired value of the variable or variables and utilizes such information in continuously using the extent of deviation as a basis for the control of the same or another variable which may or may not contribute to the change or maintenance of the original vari able being measured.

Specifically the network III), I25, IZt is sensitive to the temperature of the furnace H5 at resistance arm H4 for continuously determining such temperature and indicating it upon the index I29 and recording it upon the chart I2I. Simultaneously the motor IIB controls the position of a contact arm I II along a slidewire potentiometer N2 of the deviation network I49.

In this preferred embodiment, I desirably continuously compare the actual temperature at the element H4 with a programmed temperature to be maintained within the furnace I I5. Current and/ or potential in the loop including the winding sit and potentiometer I43 is continually compared to current and/or potential in the loop including the secondary of a transformer M4 and the potentiometer I42 which is varied by the position of the contact arm I II. Any unbalance or deviation will show up in the conductors Hi5, I i-6, to the amplifier IA'I, for controlling the heating element I22 to return the actual temperature at the resistance II l into agreement with the desired temperature dictated by the program element I3.

Reference to Fig. 11 shows the nature of a time-temperature program which may be included upon the wire I8 wherein the temperature of the furnace I I5 may be gradually brought to a predetermined value, then the temperature dwell at such value for a certain predetermined length of time and the decay of temperature to follow the same or other desired slope.

In this particular arrangement of Fig. 9, the motor IIB simultaneously positions the contact arms III, I4I indicative of actual temperature at location I I4. Movement of the arm I4I along the potentiometer I42 does not balance any circuit or network including the wires conductors Hi5, I4 5 but any balancing of the deviation circuit occurs only when the temperature within the furnace H5 has been returned to a value predicated by the wire it! and shown up: as the position of the arm I iI along the resistance I42.

In Fig. 10 I illustrate diagrammatically a further arrangement for program control of temperature within a heated container I50. The container I5fi may be supplied with a heating fluid through a conduit I5I under the control of a regulating valve I52. Temperature within the container I55 is effective upon the bulb I53 of a filledsystem including the bulb I53, a capillary led and a Bourdon tube ltd; the latter arranged to have its free end position one end of a lever I55 as temperature within the container I5Ii varies. For example, if the temperature at location I53 increases then the free end of the Bourdon tube I55 will tend to rotate counterclockwise thus moving the lever I52 in a clockwise direction and raising the stem I51 of a pneumatic pilot valve I58. The latter controls a fluid pressure within a pipe I59 for positioning the regulating valve I52. Thus, assuming that the right-hand end of the lever I56 is stationary, an increase in temperature within the container I58 will call for a closing of the valve I52 while a. decrease in temperature of the container lei! will call for an opening of the valve I52. Such action would serve to compare the actual temperature (position of the Bourdon tube I55) with a prefixed standard temperature (position of the righthand end of lever I56).

Additionally the present invention controls the right-hand of the lever I56 to position the same along a programmed path so that the position of the pilot stem I5'I becomes a measure of deviation of actual temperature from programmed temperature which is desired to maintain within the container I58.

A program wire it has a sensitive feeler winding 49 feeding an amplifier E53 which controls the direction and amount of rotation of a motor liil for positioning the right-hand end of the lever 155 and simultaneously positioning a contact arm IE2 along the balancing potentiometer I63. The arrangement may produce a temperature-time program within the container I59 of nature for example like that shown in Fig. 11.

While I have chosen to illustrate and describe certain preferred arrangements and embodiments of my invention it will be understood that these are by way of illustration only and are not to be considered as limiting.

For example, I have chosen to describe particularly that the magnetic storage media are in the nature of circular wires. It will be appreciated that such media may be in fact metallic tape or paper tape with metallic coating or similar elongated magnetic storage media. Furthermore, that a multiplicity of programs or cams may be stored in various lanes on a tape or similar media and, in known fashion, a plurality of pick-up or feeler heads may be properly located adjacent to different channels of such a. tape.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. Apparatus for controlling a lathe by relatively moving the tool and work piece, including in combination, an electric motor adapted to rotate the work piece, a second electric motor adapted to move the tool transversely relative to the work piece, a third electric motor adapted to move the tool longitudinally relative to the work piece, an elongated medium susceptible to receiving three magnetic patterns of desired motor operation related to time, means individually sensitive to said patterns located adjacent the medium, a control device for each motor, apparatus connecting each said means to one of said control devices for controlling the motors, and means for moving the medium past the sensitive means at preselected speed, said control devices for some of said motors combining speed and directional control means, said directional control means including a self-balancing circuit element driven by the controlled motor.

2. A motor control circuit, in combination, an electric motor, a source of power for said motor, a magnetized medium of considerable length having a pattern of magnetism along its length, a sensing head adjacent the medium and having an electrical output, means for moving the medium at preselected speed past the sensing head, circuit means controlled by the sensing head output for connecting the motor to the source of power, said last mentioned means including circuit components opposing said output and biased to correspond to a predetermined pattern cross sectional output magnitude, said motor being arranged for rotation in one direction with greater magnitude of bias to output and in the other direction with lesser magnitude, motor speed varying with said magnitude in either direction.

3. Apparatus for controlling a lathe by relatively moving the tool and work piece, including in combination, means arranged to travel the tool longitudinally of the work piece at a preselected uniform speed, means adapted to rotate the work piece at a preselected uniform speed, an electric motor carried longitudinally with the tool and adapted to move the tool toward or away from the work piece along a path of less than degrees to the axis of the work piece, circuit means controlling the motor and thus the direc tion and speed of movement of the tool along said path, an elongated magnetizable medium having a preapplied envelope of magnetism of patterned cross-sectional magnitude along the length of the medium representing time, means for moving said medium at a preselected speed relative to a fixed location, and a sensing means at said location responsive to the envelope magnitude passing thereby and dictating to the circuit means.

4. The combination of claim 3 wherein the path is 45 degrees.

5. Apparatus arranged to control the operation of a vertical boring mill to form a Work piece to conform to a preselected shape, including in combination, means adapted to rotate the work piece at a preselected speed, means adapted to move the tool across the work piece along a path passing through its center of rotation, an electric motor carried with the tool along said path and arranged to move the tool toward or away from the work piece along a second path less than 90 degrees from said first path, a source of power for the motor, program means controlling the direction and amount of movement of the tool by the motor, said program means including an elongated medium having an envelope of mag netism shaped in accordance with program-time, a sensing head, means to move the medium at a preselected speed past the head, circuit means controlled by said head for connecting the motor to the source of power, and means to reverse direction of rotation of the Work piece as the tool crosses the axis of rotation in its unidirectional travel along the first path.

6. Apparatus adapted to control a variable quantity, quality, position or the like, including in combination, an elongated program medium having a pattern of magnetism varying solely in intensity shaped along its length according to desired value-time relation, means for moving the medium past a location at preselected speed, a device at said location sensitive solely to the magnitude of the pattern as it passes the location and adapted to generate a potential representative thereof, means opposing said potential and a bias voltage, means amplifying the potential difierences, a motor arranged to regulate said variable, and control means for said motor responsive to the output of said amplifying means.

7. The combination of claim 6 including means determining the actual value of the variable, and circuit means continuously comparing the program value with the actual value, said circuit means also affecting the control means.

8. The combination of claim 7 wherein the control means is arranged to regulate the variable in accordance with departure of actual value from the program variable.

9. A temperature control system including in combination, means adapted to regulate the temperature, measuring means continuously determining the actual value of the temperature, an elongated magnetizable medium having a pattern of magnetism shaped to a temperature-time program, means for moving the medium past a location at a preselected speed, a device at said location sensitive to the magnitude and shape of the pattern as it passes the location, a deviation circuit continually comparing the actual with the desired value at said location, and means responsive to the deviation circuit controlling the regulating means.

10. A temperature control system including in combination, regulating means for the temperature, means continually determining the actual value of the temperature, means representing the standard temperature to be maintained, control means for the regulating means jointly responoive to the determining means and the standard means, and program means for setting the standard, said program means comprising an elongated medium having a pattern of magnetism shaped to a desired time-standard pattern, means for moving the medium past a location at preselected speed, and a device at said location sensitive to the magnitude and shape of the pattern as it passes the location, said device being connected to said control means.

11. Apparatus for controlling a lathe by relatively moving the tool and rotating workpiece, including in combination, a motor for advancing and retracting the tool, an energized potentiometer positioned by said motor, a reversing and speed controller for said motor, means providing a control signal for determining the speed and direction of rotation of said motor, circuit means opposing said signal and the potentiometer output, said controller being energized by the direction and magnitude of the potential difference in said circuit, said signal providing means comprising an elongated medium having an envelope of magnetism forming a machining pattern therealong, means sensitive to the envelope magnetism at any location along the medium, and means for progressively moving the medium past the sensitive means.

12. The apparatus as defined in claim 11 wherein said last mentioned means is an electric motor, a program selector for said motor comprising a stop and start control for the motor, a belt having control features thereon representative of said program, and means moving said belt to progressively actuate said control by successive features.

13. The apparatus as defined in claim 11 wherein said last mentioned means include a motor and reverse means for said medium, programming means for said last mentioned motor and reverse means comprising a constantly driven endless flexible element having motor start and stop and reverse means position indicators thereon, and mechanism cooperating with said indicators to control the motor start and stop and the reverse means.

14. The apparatus as defined in claim 11 wherein the lathe is provided with a second motor adapted for constant directional rotation of the leadscrew thereof during a cutting operation, and speed control means for said second motor comprising current regulating mechanism inversely under the control of the speed control device for the first motor on the lathe and independent of the direction of rotation of the first motor.

15. The apparatus of claim 1 wherein the elongated medium is in tape form and has three parallel magnetic pattern lanes.

16. The apparatus of claim 1 wherein the elongated medium comprises three separate strands each comprising a magnetic pattern lane.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,213,108 Pollard Aug. 27, 1940 2,275,317 Ryder Mar. 3, 1942 2,310,955 Hornfeck Feb. 16, 1943 2,423,440 DeNeergaard July 8, 1947 2,475,245 Leaver July 5, 1949 2,511,956 Wetzel June 20, 1950 2,537,770 Livingston Jan. 9, 1951 

